ADS-B Multilateration Metric Fusion for Surveillance Validation

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Solution Overview

Problem

Current methods lack a standardized approach to combine and compare the performance metrics of different aircraft surveillance systems, such as ADS-B and multilateration, making it difficult to determine their accuracy and integrity for reliable backup systems.

Innovation Solution

The system integrates ADS-B and multilateration by using ADS-B as the primary means of surveillance and multilateration as a backup, with both systems providing performance metrics like Navigation Accuracy Category (NAC), Navigation Integrity Category (NIC), and Surveillance Integrity Level (SIL), allowing for comparison and fusion of data to ensure accurate tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ADS-B is used as the primary surveillance system, then the system can provide accurate real-time navigation information, but there is no standardized method to validate or backup the ADS-B data

Engineering Contradiction:
Improvesurveillance accuracyVSAvoidsystem validation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a ground-based multilateration system as an intermediary validation mechanism. This independent surveillance system receives the same aircraft transponder signals and calculates position through time difference of arrival (TDOA) measurements, providing an objective backup that does not rely on aircraft-reported navigation data. The multilateration system acts as a mediator to verify ADS-B position accuracy without requiring direct access to aircraft navigation systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously comparing ADS-B reported positions with multilateration-calculated positions. When discrepancies exceed predetermined thresholds, the system generates alerts or overrides the ADS-B data. This closed-loop feedback mechanism ensures ongoing validation and allows the system to self-correct or flag potential ADS-B failures in real-time.

Inventive Principle:
Principle #23Feedback

2Reliability

If multilateration is implemented as a backup system, then ADS-B accuracy can be validated, but there is no standardized method to combine performance metrics from different surveillance systems

Engineering Contradiction:
Improvesurveillance backup capabilityVSAvoidperformance metric comparability
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent establishes a universal performance metric framework that can evaluate both ADS-B and multilateration systems using common criteria. By defining standardized figures of merit that apply across different surveillance technologies, the system enables apples-to-apples comparison and integration of performance data from heterogeneous sources, facilitating unified surveillance management.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system transforms diverse surveillance performance parameters into a standardized metric format. By converting different measurement types (position accuracy, velocity accuracy, integrity metrics) from ADS-B and multilateration into comparable standardized parameters, the system enables mathematical combination and objective evaluation of mixed surveillance data sources.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If both ADS-B and multilateration systems operate independently, then each system maintains its own performance metrics, but it is difficult to determine which system provides more accurate data

Engineering Contradiction:
Improvesystem independenceVSAvoidaccuracy comparison capability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent merges the independent performance metrics of ADS-B and multilateration systems into a unified evaluation framework. By combining the figure of merit calculations from both systems and applying weighted integration based on their respective accuracies, the system determines the most reliable position estimate while preserving the independence and operational characteristics of each individual surveillance system.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1884908B1Method and system to extend ADS performance metrics
Publication Date: 2010.09.29 ERA SYSTEMS CORPORATION
  • EP1884908B1 patent drawingFigure 1
  • EP1884908B1 patent drawingFigure 2
  • EP1884908B1 patent drawingFigure 3

AI summary

A method and system are provided for measuring and monitoring performance metrics of a non-ADS-B tracking system and generating performance metrics for the non-ADS-B tracking system in terms of ADS-B equivalent performance metrics. An aircraft (100) transmits various transponder-based or other signals (110) which are received at multiple ground stations (200, 210), some of which may be ADS-B stations (210) or both ADS-B and multilateration stations (200). ADS-B signals may contain performance metrics which are passed on from ADS-B station (210) to an ADS-B processor (300), which outputs aircraft-derived metrics (350). ADS-B signals and all other transponder signals are also received at all ground stations (200, 210), time-stamped, and sent to a multilateration processor (310), which generates multilateration metrics (360). Therefore two streams of information are passed onto ATC system processor (400) containing the ADS-B aircraft-derived metrics (350) and multilateration-derived metrics (360). The ATC system processor (400) may then be configured to pass along both sets of messages (410) to the ATC system, or to select a combination or fusion of the best metrics and tracking information for an aircraft (100).